French researchers find link between DDT exposure and Parkinson’s Disease

June 16, 2010

French researchers looked at men who possess a gene that predisposes them to Parkinson’s Disease, and found that DDT exposure correlates with actual onset of the disease.

(Reuters) – Men with certain genetic variations who were exposed to some toxic pesticides which are now largely banned run an increased risk of developing Parkinson’s disease, French scientists said Monday.

Researchers found that among men exposed to pesticides such as DDT, carriers of the gene variants were three and a half times more likely to develop Parkinson’s than those with the normal version of the gene.

The scientists, whose work was published in the Archives of Neurology journal, think the brains of people with the gene variant fail to flush out toxins as efficiently as those with normal versions of the gene, suggesting environmental as well as genetic factors are important in the risk of Parkinson’s.

DDT, which belongs to a group of pesticides known as organochlorines, is one of the “Dirty Dozen” chemicals banned by a 2001 United Nations convention after it was found to be a toxin that can suppress the immune system.

It is infamous for threatening bird populations by thinning eggshells, and has also been linked to increase risks in humans of diseases such as cancer and Parkinson’s — an incurable and often deadly brain disease.

But exemptions to the DDT ban are allowed in many developing nations because it so effective in killing mosquitoes. DDT’s Swiss inventor Paul Hermann Muller won the 1948 Nobel Prize for Medicine — before its wider toxic effects were known.

Alexis Elbaz and Fabien Dutheil, of France’s National Institute for Health and Medical Research (INSERM) studied 101 men with Parkinson’s and 234 without the disease to look at links between organochlorine exposure and Parkinson’s disease.

The study included only men, and all of them had had high levels of exposure to pesticides through their work as farmers.

The scientists found the link was around 3.5 times stronger in men who carried two copies of a gene known as ABCB1, which plays a role in helping the brain flush out dangerous chemicals.

File that one away for the next time some yahoo claims there are no harmful effects to health from DDT.  The study probably could not distinguish between heavy exposure to pesticides and the much lighter exposure assumed to result from Indoor Residual Spraying of DDT, such as is used in some places in Africa in the fight against malaria.

Anybody got a copy of the actual study, in English?


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